New Chip Design Promises Terahertz Processors

Scientists at the University of Rochester have come up with a new "ballistic computing" chip design that could lead to 3,000-gigahertz — that's 3-terahertz — processors that produce very little heat.

Marc Feldman, professor of computer engineering at the university, characterizes the design, the Ballistic Deflection Transistor (BDT), as radical. "There's a real problem for standard transistors to keep shrinking," he says. The BDT doesn't have a capacitance layer that becomes problematic at very small scales the way current transistor designs do.

Quentin Diduck, the graduate student at the University who came up with the idea, describes the BDT as the next step on the evolutionary track after relays, tubes, and semiconductors.

The BDT, according to the University of Rochester, "[bounces] the electrons into their chosen trajectories — using inertia to redirect for 'free,' instead of wrestling the electrons into place with brute energy." It functions more as an intersection for electrons than as a device that expends energy to stop and start them. Because of this approach, far less power is required.

The BDT relies on a layer of a semiconductor material called a "2D electron gas," which facilitates the transit of electrons without the interference of impurities.Feldman says he expects the BDT to put out very little heat. "We don't have the mathematics to predict how small this is going to be," he says. "But the currents it would take are very small. So the power has to be small."

The heat generation for early versions of the design should be around a few microwatts per transistor, Feldman estimates, orders of magnitude less than current high-frequency transistors. "Now that's without doing any tricks to cut down the power," he says. "There are great opportunities for low-power design. But that's the future."

Companies that maintain large, energy-hungry data centers like Google, Microsoft, and Yahoo, to name a few, are no doubt looking forward to that day.

The BDT still has a ways to go before it ends up in PCs and servers, however. "Up to now this has been a one-graduate-student effort," explains Feldman. "We don't have any transistor behavior yet, but probably soon."

The National Science Foundation has just granted the University of Rochester team $1.1 million to develop a prototype.0